Phasor synthesis type flexible interconnection transformer topological structure and control method

Abstract

The invention discloses a phasor synthesis type flexible interconnection transformer topological structure and a control method. The phasor synthesis type flexible interconnection transformer topological structure comprises a first parallel branch and a second parallel branch which are connected into an alternating current input end in parallel. Each branch is composed of two rotating phase-shifting transformer units, rotor windings of the two rotating phase-shifting transformer units are connected in parallel, and stator windings of the two rotating phase-shifting transformer units are connected in series to form an output port. The internal rotors of the two output ports are respectively driven by independent servo motors to rotate synchronously, and the control module generates corresponding rotating speed instructions according to power control targets of the ports. The structure is based on the phasor synthesis principle, and continuous and accurate adjustment of voltage and power flow is achieved through mechanical rotation conversion. The defects that traditional power electronic equipment is high in harmonic pollution and a mechanical transformer is slow in response are effectively overcome, and the controllability and economical efficiency of a system are remarkably improved while the advantages of high reliability and low loss of a full-electromagnetic structure are kept; and an efficient and compatible flexible interconnection solution is provided for a complex power distribution network containing high-proportion renewable energy sources.

Description

Technical Field

[0001] This invention belongs to the field of coordinated configuration technology of flexible interconnection and voltage transformation in power distribution networks, and particularly relates to a phasor synthesis type flexible interconnection transformer topology and control method. Background Technology

[0002] In recent years, with the advancement of new power system construction, the large-scale application of power electronic equipment in active distribution networks has significantly improved the controllability of the grid. However, its inherent harmonic pollution and electromagnetic noise problems seriously threaten the purity of the grid and restrict the safe and efficient access of high-proportion distributed power sources (such as photovoltaic and wind power). Meanwhile, traditional transformers, limited by mechanical discrete regulation and second-level response speeds, struggle to meet the future distribution network's demands for flexible and precise control of voltage and power flow. Against this backdrop, developing new flexible interconnected devices (FIDs) that combine high controllability and electromagnetic compatibility has become crucial for constructing efficient and low-loss new distribution systems. Currently, there is no clear and unified definition for flexible interconnection transformers (FITs). They are considered to be flexible interconnected devices capable of achieving flexible, bidirectional, and precise control of power flow on top of the traditional transformer's voltage transformation and electrical isolation functions.

[0003] Current research on FITs mainly focuses on two major technical routes: power electronic and electromagnetic. While power electronic FITs (such as power electronic transformers (PETs)) offer advantages in rapid response and flexible adjustment, they generally suffer from severe harmonic pollution, weak shock resistance, and high operation and maintenance costs. In electromagnetic FITs, a novel rotary interconnection transformer (NRIT) topology, consisting of two parallel RPSTs (rotary phase shifting transformers), achieves continuous regulation of the output voltage through mechanical rotation. This improves control accuracy while maintaining the reliability of electromagnetic equipment, but it still has limitations in terms of dynamic response speed and adaptability to complex power grid scenarios.

[0004] In addition, there is a voltage source type reactive power compensator scheme based on a rotating phase-shifting transformer in the existing technology. Although this scheme has continuous and bidirectional reactive power regulation capabilities and is easy to implement for high voltage and large capacity, its design is mainly used to replace the converter for voltage control, which essentially sacrifices the original power flow regulation capability. Furthermore, some designs introduce non-fully electromagnetic structures, which may lead to harmonic pollution problems.

[0005] In summary, existing technologies cannot fundamentally address the multiple requirements of high controllability, rapid response, low harmonic pollution, high reliability, and low-cost maintenance. Therefore, there is an urgent need to propose a phasor synthesis-type flexible interconnection transformer topology and control method. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a phasor synthesis type flexible interconnection transformer topology, comprising:

[0007] The first parallel branch and the second parallel branch are connected in parallel and then connected to the AC input terminal;

[0008] The first parallel branch includes a first rotating phase-shifting transformer unit and a second rotating phase-shifting transformer unit. The rotor windings of the first rotating phase-shifting transformer unit and the rotor windings of the second rotating phase-shifting transformer unit are connected in parallel. The stator windings of the first rotating phase-shifting transformer unit and the stator windings of the second rotating phase-shifting transformer unit are connected in series to form a first output port.

[0009] The second parallel branch includes a third rotating phase-shifting transformer unit and a fourth rotating phase-shifting transformer unit. The rotor windings of the third rotating phase-shifting transformer unit and the fourth rotating phase-shifting transformer unit are connected in parallel. The stator windings of the third rotating phase-shifting transformer unit and the stator windings of the fourth rotating phase-shifting transformer unit are connected in series to form a second output port.

[0010] A first servo motor and a second servo motor, wherein the first servo motor is used to drive the rotors of the first rotating phase-shifting transformer unit and the second rotating phase-shifting transformer unit to rotate synchronously, and the second servo motor is used to drive the rotors of the third rotating phase-shifting transformer unit and the fourth rotating phase-shifting transformer unit to rotate synchronously.

[0011] The control module is used to generate speed control commands for the first servo motor and the second servo motor based on the power control targets of the first output port and the second output port.

[0012] Optionally, the process of generating speed control commands for the first servo motor and the second servo motor includes:

[0013] Based on the transmission power control target of the first output port or the second output port, determine the injection voltage target value of the corresponding output port;

[0014] The target value of the injected voltage is mapped and decomposed into the corresponding mechanical angle command of the servo motor;

[0015] Based on the mechanical angle command, a corresponding servo motor speed control command is generated.

[0016] Optionally, the process of determining the injection voltage target value of the corresponding output port based on the transmission power control target of the first output port or the second output port includes:

[0017] Based on the target transmission power, equipment inductive reactance, and input voltage, the amplitude and phase angle of the injected voltage required for the line to reach the target transmission power are calculated.

[0018] Optionally, the process of mapping and decomposing the injected voltage target value into the corresponding mechanical angle command of the servo motor includes:

[0019] Based on the magnitude of the target value of the injected voltage and the voltage change relationship of the rotating phase-shifting transformer unit, the required combined stator voltage phasor of the first rotating phase-shifting transformer unit and the second rotating phase-shifting transformer unit is calculated;

[0020] The target rotor angle of the first servo motor is determined based on the synthesized stator voltage phasor.

[0021] Optionally, the first output port serves as a voltage conversion port for connecting to a first load;

[0022] The second output port serves as a power flow control port, used to connect to the second load or grid-connected line.

[0023] This invention also provides a control method for a phasor-combining flexible interconnection transformer, applied to a phasor-combining flexible interconnection transformer topology, comprising the following steps:

[0024] Based on the transmission power control target of the target output port, determine the corresponding injection voltage target value;

[0025] The target value of the injected voltage is mapped and decomposed into mechanical angle commands that drive the servo motors of the corresponding rotating phase-shifting transformer unit groups;

[0026] The servo motor speed is controlled according to the mechanical angle command to adjust the rotor angle of the corresponding rotating phase-shifting transformer unit, thereby synthesizing the required injection voltage at the target output port.

[0027] Optionally, the process of determining the corresponding injection voltage target value based on the transmission power control target of the target output port includes:

[0028] Obtain the target transmission power of the target output port;

[0029] Based on the target transmission power, device inductive reactance, and input voltage, the amplitude and phase angle of the injection voltage required to make the line reach the target transmission power are calculated and used as the target value of the injection voltage.

[0030] Optionally, the process of mapping and decomposing the injected voltage target value into mechanical angle commands for driving the servo motors of the corresponding rotating phase-shifting transformer unit group includes:

[0031] Based on the magnitude of the target value of the injected voltage and the voltage change relationship of the rotating phase-shifting transformer unit, the required stator-side composite voltage phasor is calculated;

[0032] Based on the phase of the synthesized voltage phasor on the stator side, the target rotor angle to be driven by the servo motor is determined as a mechanical angle command.

[0033] Optionally, the process of controlling the rotational speed of the servo motor according to the mechanical angle command includes:

[0034] The mechanical angle command is compared with the current rotor angle of the rotating phase-shifting transformer unit to obtain the angle deviation;

[0035] Based on the angle deviation, a speed control signal for the servo motor is generated by the speed regulator.

[0036] Optionally, the method further includes:

[0037] Set independent transmission power control targets for the first output port and the second output port respectively;

[0038] For the control objective of the first output port, the first servo motor is driven to adjust the rotor angle of the rotating phase-shifting transformer unit in the first parallel branch, and the first injection voltage is synthesized at the first output port;

[0039] To achieve the control objective of the second output port, the second servo motor is driven to adjust the rotor angle of the rotating phase-shifting transformer unit in the second parallel branch, and a second injection voltage is synthesized at the second output port.

[0040] The synthesis of the first injection voltage and the second injection voltage is independent of each other.

[0041] Compared with the prior art, the present invention has the following advantages and technical effects:

[0042] This invention, based on phasor synthesis technology, designs a three-port topology consisting of two sets of rotating phase-shifting transformer units and proposes a three-layer control architecture of "power-voltage closed loop - synthesized phasor decomposition - mechanical speed coordination." This fundamentally overcomes the technical bottlenecks of severe harmonic pollution in traditional power electronic equipment and slow dynamic response of electromagnetic transformers. It maintains the high reliability, low loss, and strong impact resistance of the all-electromagnetic structure while achieving rapid, continuous, and precise regulation of distribution network voltage and power flow. At the same time, its unique topology design significantly optimizes the device in terms of insulation requirements, power device capacity, and manufacturing costs, and provides the ability to independently control multiple ports. Thus, it provides a highly controllable, highly compatible, and highly economical flexible interconnection solution for complex distribution network scenarios with a high proportion of renewable energy access. Attached Figure Description

[0043] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0044] Figure 1 This is a schematic diagram of the topology of the rotating phase-shifting transformer unit (RPST) and its single-phase equivalent circuit diagram in an embodiment of the present invention; wherein, (a) is a schematic diagram of the topology connection of the RPST; and (b) is a single-phase equivalent circuit diagram of the RPST.

[0045] Figure 2 The diagram shows the topology of a power electronic flexible interconnect transformer in the prior art; where (a) is the topology of a three-port power electronic transformer (PET); and (b) is the topology of a PET based on a modular multilevel converter (MMC).

[0046] Figure 3 These are schematic diagrams of two topologies of the phasor synthesis flexible interconnection transformer (NFIT) proposed in the embodiments of the present invention; wherein, (a) is a three-port novel rotating interconnection transformer (NRIT) topology; and (b) is a multi-RPST modular topology (M-RPST) structure.

[0047] Figure 4 Corresponding to the embodiments of the present invention Figure 3 (a) is the equivalent circuit diagram and voltage phasor synthesis diagram of the three-port NRIT topology; where (a) is the equivalent circuit diagram of the three-port NRIT; and (b) is the voltage phasor synthesis diagram.

[0048] Figure 5 Corresponding to the embodiments of the present invention Figure 3 (b) shows the equivalent circuit and voltage phasor synthesis diagram of the M-RPST topology; where (a) is the equivalent circuit diagram of the M-RPST and (b) is its voltage phasor synthesis diagram.

[0049] Figure 6 This is a schematic diagram of the NFIT control line transmission power in an embodiment of the present invention, illustrating the relationship between the injected voltage and the line power;

[0050] Figure 7 This is a schematic diagram of the three-layer control architecture of "power voltage closed loop - synthetic phasor decomposition - mechanical speed coordination" proposed in the embodiments of the present invention. Detailed Implementation

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0053] Example 1

[0054] This embodiment provides a phasor synthesis type flexible interconnection transformer topology, including:

[0055] The first parallel branch and the second parallel branch are connected in parallel and then connected to the AC input terminal;

[0056] The first parallel branch includes a first rotating phase-shifting transformer unit and a second rotating phase-shifting transformer unit. The rotor windings of the first rotating phase-shifting transformer unit and the rotor windings of the second rotating phase-shifting transformer unit are connected in parallel. The stator windings of the first rotating phase-shifting transformer unit and the stator windings of the second rotating phase-shifting transformer unit are connected in series to form a first output port.

[0057] The second parallel branch includes a third rotating phase-shifting transformer unit and a fourth rotating phase-shifting transformer unit. The rotor windings of the third rotating phase-shifting transformer unit and the fourth rotating phase-shifting transformer unit are connected in parallel. The stator windings of the third rotating phase-shifting transformer unit and the stator windings of the fourth rotating phase-shifting transformer unit are connected in series to form a second output port.

[0058] A first servo motor and a second servo motor, wherein the first servo motor is used to drive the rotors of the first rotating phase-shifting transformer unit and the second rotating phase-shifting transformer unit to rotate synchronously, and the second servo motor is used to drive the rotors of the third rotating phase-shifting transformer unit and the fourth rotating phase-shifting transformer unit to rotate synchronously.

[0059] The control module is used to generate speed control commands for the first servo motor and the second servo motor based on the power control targets of the first output port and the second output port.

[0060] The feasible process of generating speed control commands for the first servo motor and the second servo motor includes:

[0061] Based on the transmission power control target of the first output port or the second output port, determine the injection voltage target value of the corresponding output port;

[0062] The target value of the injected voltage is mapped and decomposed into the corresponding mechanical angle command of the servo motor;

[0063] Based on the mechanical angle command, a corresponding servo motor speed control command is generated.

[0064] Furthermore, the process of determining the target value of the injection voltage of the corresponding output port based on the transmission power control target of the first output port or the second output port includes:

[0065] Based on the target transmission power, equipment inductive reactance, and input voltage, the amplitude and phase angle of the injected voltage required for the line to reach the target transmission power are calculated.

[0066] Furthermore, the process of mapping and decomposing the injected voltage target value into the corresponding mechanical angle command of the servo motor includes:

[0067] Based on the amplitude of the target injected voltage and the voltage change relationship of the rotating phase-shifting transformer unit, the required combined stator voltage phasor of the first and second rotating phase-shifting transformer units is calculated; based on the combined stator voltage phasor, the target rotor angle of the first servo motor is determined.

[0068] In practice, the first output port serves as a voltage conversion port for connecting to the first load; the second output port serves as a power flow control port for connecting to the second load or a grid-connected line.

[0069] As a feasible implementation method, existing research cannot overcome the technical bottlenecks of harmonic interference in traditional power electronic devices and the response lag of mechanical transformers. RPST devices, however, offer advantages such as high controllability and electromagnetic compatibility, and can replace existing power electronic devices, significantly improving power quality. Economically, their all-electromagnetic structure features low maintenance costs and a long lifespan, reducing overall costs compared to traditional solutions. Based on phasor synthesis technology, the combined topology of RPST can further achieve continuous electromagnetic control, replacing traditional power electronic switching modulation and realizing technical advantages in harmonic suppression and regulation capabilities.

[0070] This embodiment aims to design a novel FIT based on RPST based on the duality principle, analyze the dynamic control law of phasor synthesis type FIT, and propose a three-layer control architecture of "power voltage closed loop - synthesis phasor decomposition - mechanical speed coordination".

[0071] Specifically, the topology design of a phasor synthesis type flexible interconnection transformer:

[0072] Figure 1 (a) shows the topology of the RPST, where the rotor winding is connected in parallel with the power supply line as the primary side, while the stator winding is connected in series with the line as the secondary side. Based on the principle of electromagnetic induction, by precisely controlling the mechanical rotation angle of the RPST rotor, a stator voltage phasor with constant amplitude and continuously adjustable phase within a 360° range can be injected into the line.

[0073] Figure 1 Figure (b) shows the single-phase equivalent circuit of the RPST. In this circuit, This represents the total rotor-side current. This refers to the stator-side current. This represents the voltage after RPST voltage transformation. Additionally, Z... rt Z is the sum of the parallel line impedance and the equivalent impedance referred to the rotor side; st is the stator-side impedance, and k represents the voltage turns ratio of RPST.

[0074] If the influence of the transformer excitation current is ignored, based on the traditional transformer analysis principle, the following relationship can be obtained:

[0075] (1)

[0076] (2)

[0077] (3)

[0078] in, .

[0079] Then, based on the duality principle, the topology design of the electromagnetic FIT based on RPST is carried out. The power electronic and electromagnetic FIT topologies are as follows: Figure 2 , Figure 3 As shown.

[0080] Figure 2 Figure (a) shows a three-port PET topology, where all three ports are AC ports, and the ports are interleaved via DC nodes to achieve energy exchange between the ports; therefore, Figure 3(a) of the paper proposes a three-port NRIT topology and adopts a hybrid access method: the rotor-side windings of the two NRIT units are not connected in parallel independently, but are connected in series to the line; at the same time, the two RPSTs inside each NRIT still maintain the traditional structure of parallel connection on the rotor side and series connection on the stator side.

[0081] Compared to the traditional parallel connection of two NRITs, the three-port NRIT designed in this embodiment only requires each NRIT to withstand half of the system voltage on its primary side, significantly reducing insulation requirements and consequently lowering the capacity of the power devices. Furthermore, this connection method ensures that the current flowing through the two NRITs is exactly the same, achieving synchronous power transmission. The core advantage of the three-port NRIT lies in its flexible operating mode. It can divide the system into two independent electrical channels: one channel can act as a conventional transformer, completing the predetermined voltage transformation and power transmission tasks; simultaneously, the other channel acts as a power flow controller, dynamically adjusting the active and reactive power on its lines. This allows a single three-port NRIT device to simultaneously address both steady-state power supply and dynamic optimization of the power grid.

[0082] Figure 2 Figure (b) shows a PET topology based on MMC. MMC has advantages such as modularity, multi-level operation, easy redundancy, high AC port power quality, and high operating efficiency. Its application in PET can improve system reliability, efficiency, and performance, making it suitable for high-voltage, high-power applications. (Reference) Figure 2 (b) in the middle proposes Figure 3 In the multi-rotary phase shifting transformer (M-RPST) topology (b), the rotor-side windings of each RPST module are connected in parallel to the network to achieve a unified voltage reference and power extraction, while the stator-side windings are connected in series and injected into the line. The angle of all rotors is synchronously controlled by the mechanical shaft, so that the stator-side compensation voltages of each module are synthesized into a compensation voltage with controllable amplitude and phase.

[0083] Both RPSTs in the NRIT are single-point-of-failure units. Employing the redundancy design of M-RPSTs improves transformer reliability. Because M-RPSTs possess multiple degrees of freedom in control (stator-rotor relative angles), they can not only synthesize the total compensation voltage but also more precisely optimize internal circulating current and power distribution. Finally, mass production of standard-capacity RPST modules reduces design and manufacturing costs and shortens the manufacturing cycle. However, as a traditional distribution network step-down transformer, the advantage of secondary-side series synthesis of high voltage is not reflected on the receiving end. Using M-RPSTs as step-up transformers for distributed generation allows them to fully leverage their voltage transformation and power flow control functions in complex, active grid interconnection nodes. Facing the development of larger capacities and higher voltages in distributed generation, M-RPSTs can flexibly match the ever-increasing capacity and different grid connection voltage levels by increasing or decreasing the number of sub-modules.

[0084] The phasor synthesis control architecture for the novel flexible interconnected transformer proposed in this embodiment is feasible:

[0085] right Figure 3 The topology unfolding study and analysis of the novel flexible interconnection transformer (NFIT) proposed in this paper. Figure 3 The equivalent circuits and voltage phasor composition diagrams corresponding to topologies (a) and (b) are shown below. Figure 4 , Figure 5 As shown.

[0086] The two output ports of the three-port NRIT share the same input port. , and , They were synthesized into and While achieving energy exchange at the three ports, each port independently completes voltage transformation.

[0087] M-RPST modularizes the RPST, allowing the selection of the number of RPSTs based on the secondary voltage level and capacity requirements. Through multiple degrees of control freedom, it flexibly synthesizes the target voltage. .

[0088] Figure 6 For the scenario of NFIT controlling line power, the voltage on the left side of line L1 NFIT output voltage Under the premise that ωL >> R within NRIT, the transmission power of the line at this time is

[0089] (4)

[0090] According to equations (3) and (4), NFIT can be directly controlled by adjusting the stator-rotor relative angle α of RPST. The amplitude and phase are adjusted to achieve voltage and power flow regulation of line L1.

[0091] Based on this, a three-layer control architecture for NFIT, namely "power voltage closed loop - synthetic phasor decomposition - mechanical speed coordination", is established. Figure 7 As shown. The top layer is the power closed-loop control layer, where the power loop controls the line-transmitted power P. 3ref +jQ 3ref As the control target, the solution is obtained according to equation (4). The voltage loop control target is used as the intermediate layer, which is the voltage closed-loop control layer. It maps and decomposes the electrical quantity commands output from the upper layer into the stator-rotor relative angle mechanical quantity command α of RPST. iref The lower layer is the speed coordination control layer, which is responsible for executing the angle commands issued by the middle layer and outputting the actual relative angle α between the stator and rotor through the speed coordination of the servo motor. i .

[0092] This embodiment proposes a combined topology of RPST to further realize electromagnetic continuous control, replacing traditional power electronic switch modulation, and achieving technical advantages in harmonic suppression and regulation capabilities. The beneficial effects of this technical solution include:

[0093] Current research cannot overcome the technical bottlenecks of harmonic interference in traditional power electronic equipment and the response lag of mechanical transformers. RPST devices, however, offer advantages such as high controllability and electromagnetic compatibility, and can replace existing power electronic equipment, significantly improving power quality. Economically, their all-electromagnetic structure features low maintenance costs and a long lifespan, reducing overall costs compared to traditional solutions. Compared to traditional three-port topologies, the proposed three-port NRIT topology requires each NRIT primary side to withstand only half the system voltage, significantly reducing insulation requirements and the capacity of supporting power devices, while achieving synchronous power transmission and flexible operating modes. The proposed M-RPST topology compensates for the capacity limitations of NRITs, reduces costs, and improves reliability. Finally, a three-layer control architecture of "power-voltage closed loop - synthetic phasor decomposition - mechanical speed coordination" provides a unified control strategy for novel flexible interconnected transformers, offering a highly reliable and low-loss solution for the safe operation of distribution networks with high proportions of renewable energy integration.

[0094] On the other hand, this embodiment also provides a control method for a phasor-synthetic flexible interconnection transformer, applied to a phasor-synthetic flexible interconnection transformer topology, including the following steps:

[0095] Based on the transmission power control target of the target output port, determine the corresponding injection voltage target value;

[0096] The target value of the injected voltage is mapped and decomposed into mechanical angle commands that drive the servo motors of the corresponding rotating phase-shifting transformer unit groups;

[0097] The servo motor speed is controlled according to the mechanical angle command to adjust the rotor angle of the corresponding rotating phase-shifting transformer unit, thereby synthesizing the required injection voltage at the target output port.

[0098] The feasible process of determining the corresponding injection voltage target value based on the transmission power control target of the target output port includes:

[0099] Obtain the target transmission power of the target output port; based on the target transmission power, device inductive reactance, and input voltage, calculate the amplitude and phase angle of the injection voltage required to make the line reach the target transmission power, and use them as the target value of the injection voltage.

[0100] The feasible process of mapping and decomposing the injected voltage target value into mechanical angle commands for driving the servo motors of the corresponding rotating phase-shifting transformer unit groups includes:

[0101] Based on the amplitude of the target injected voltage and the voltage change relationship of the rotating phase-shifting transformer unit, the required stator-side composite voltage phasor is calculated; based on the phase of the stator-side composite voltage phasor, the target rotor angle to be driven by the servo motor is determined as a mechanical angle command.

[0102] The feasible process of controlling the rotational speed of the servo motor according to the mechanical angle command includes:

[0103] The mechanical angle command is compared with the current rotor angle of the rotating phase-shifting transformer unit to obtain the angle deviation; based on the angle deviation, a speed control signal for the servo motor is generated through the speed regulator.

[0104] The method may also include:

[0105] Set independent transmission power control targets for the first output port and the second output port respectively;

[0106] For the control objective of the first output port, the first servo motor is driven to adjust the rotor angle of the rotating phase-shifting transformer unit in the first parallel branch, and the first injection voltage is synthesized at the first output port;

[0107] To achieve the control objective of the second output port, the second servo motor is driven to adjust the rotor angle of the rotating phase-shifting transformer unit in the second parallel branch, and a second injection voltage is synthesized at the second output port.

[0108] The synthesis of the first injection voltage and the second injection voltage is independent of each other.

[0109] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A phasor synthesis type flexible interconnection transformer topology, characterized in that, include: The first parallel branch and the second parallel branch are connected in parallel and then connected to the AC input terminal; The first parallel branch includes a first rotating phase-shifting transformer unit and a second rotating phase-shifting transformer unit. The rotor windings of the first rotating phase-shifting transformer unit and the rotor windings of the second rotating phase-shifting transformer unit are connected in parallel. The stator windings of the first rotating phase-shifting transformer unit and the stator windings of the second rotating phase-shifting transformer unit are connected in series to form a first output port. The second parallel branch includes a third rotating phase-shifting transformer unit and a fourth rotating phase-shifting transformer unit. The rotor windings of the third rotating phase-shifting transformer unit and the fourth rotating phase-shifting transformer unit are connected in parallel. The stator windings of the third rotating phase-shifting transformer unit and the stator windings of the fourth rotating phase-shifting transformer unit are connected in series to form a second output port. A first servo motor and a second servo motor, wherein the first servo motor is used to drive the rotors of the first rotating phase-shifting transformer unit and the second rotating phase-shifting transformer unit to rotate synchronously, and the second servo motor is used to drive the rotors of the third rotating phase-shifting transformer unit and the fourth rotating phase-shifting transformer unit to rotate synchronously. The control module is used to generate speed control commands for the first servo motor and the second servo motor based on the power control targets of the first output port and the second output port.

2. The phasor synthesis type flexible interconnection transformer topology according to claim 1, characterized in that, The process of generating speed control commands for the first servo motor and the second servo motor includes: Based on the transmission power control target of the first output port or the second output port, determine the injection voltage target value of the corresponding output port; The target value of the injected voltage is mapped and decomposed into the corresponding mechanical angle command of the servo motor; Based on the mechanical angle command, a corresponding servo motor speed control command is generated.

3. The phasor synthesis type flexible interconnection transformer topology according to claim 2, characterized in that, The process of determining the injection voltage target value of the corresponding output port based on the transmission power control target of the first output port or the second output port includes: Based on the target transmission power, equipment inductive reactance, and input voltage, the amplitude and phase angle of the injected voltage required for the line to reach the target transmission power are calculated.

4. The phasor synthesis type flexible interconnection transformer topology according to claim 2, characterized in that, The process of mapping and decomposing the injected voltage target value into the corresponding mechanical angle command of the servo motor includes: Based on the magnitude of the target value of the injected voltage and the voltage change relationship of the rotating phase-shifting transformer unit, the required combined stator voltage phasor of the first rotating phase-shifting transformer unit and the second rotating phase-shifting transformer unit is calculated; The target rotor angle of the first servo motor is determined based on the synthesized stator voltage phasor.

5. The phasor synthesis type flexible interconnection transformer topology according to claim 1, characterized in that, The first output port serves as a voltage conversion port for connecting to the first load; The second output port serves as a power flow control port, used to connect to the second load or grid-connected line.

6. A control method for a phasor-synthetic flexible interconnection transformer, applied to the phasor-synthetic flexible interconnection transformer topology as described in any one of claims 1-5, characterized in that, Includes the following steps: Based on the transmission power control target of the target output port, determine the corresponding injection voltage target value; The target value of the injected voltage is mapped and decomposed into mechanical angle commands that drive the servo motors of the corresponding rotating phase-shifting transformer unit groups; The servo motor speed is controlled according to the mechanical angle command to adjust the rotor angle of the corresponding rotating phase-shifting transformer unit, thereby synthesizing the required injection voltage at the target output port.

7. The control method according to claim 6, characterized in that, The process of determining the corresponding injection voltage target value based on the transmission power control target of the target output port includes: Obtain the target transmission power of the target output port; Based on the target transmission power, device inductive reactance, and input voltage, the amplitude and phase angle of the injection voltage required to make the line reach the target transmission power are calculated and used as the target value of the injection voltage.

8. The control method according to claim 6, characterized in that, The process of mapping and decomposing the injected voltage target value into mechanical angle commands for driving the servo motors of the corresponding rotating phase-shifting transformer unit group includes: Based on the magnitude of the target value of the injected voltage and the voltage change relationship of the rotating phase-shifting transformer unit, the required stator-side composite voltage phasor is calculated; Based on the phase of the synthesized voltage phasor on the stator side, the target rotor angle to be driven by the servo motor is determined as a mechanical angle command.

9. The control method according to claim 6, characterized in that, The process of controlling the rotational speed of the servo motor according to the mechanical angle command includes: The mechanical angle command is compared with the current rotor angle of the rotating phase-shifting transformer unit to obtain the angle deviation; Based on the angle deviation, a speed control signal for the servo motor is generated by the speed regulator.

10. The control method according to claim 6, characterized in that, The method further includes: Set independent transmission power control targets for the first output port and the second output port respectively; For the control objective of the first output port, the first servo motor is driven to adjust the rotor angle of the rotating phase-shifting transformer unit in the first parallel branch, and the first injection voltage is synthesized at the first output port; To achieve the control objective of the second output port, the second servo motor is driven to adjust the rotor angle of the rotating phase-shifting transformer unit in the second parallel branch, and a second injection voltage is synthesized at the second output port. The synthesis of the first injection voltage and the second injection voltage is independent of each other.

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